1. Field of the Invention
This invention relates to a weft storage apparatus for storing a weft yarn of a predetermined length preceding to supplying thereof to a shuttleless loom, and more particularly to a weft yarn end retaining device in a rotary drum type weft storing apparatus.
2. Prior Art
In an air jet loom or a water jet loom, it is required to store a weft yarn of a predetermined length preceding to supplying thereof. To this end, a weft storing apparatus is located adjacent a yarn supply source side of a weft feeding nozzle. Such weft storage apparatus may be of an air sucking or jetting type, a fixed drum type, a rotary drum type and so on. A weft storage apparatus of the rotary drum type has an advantage that reduction of the speed and stopping of a weft yarn upon completion of supplying thereof is effected so smoothly that breakage of a weft yarn occurs seldom during weaving at a high speed, resulting in an excellent operability. However, such a rotary drum type weft storage apparatus requires a yarn end holding device for holding an end of a weft yarn while it is being wound up on a yarn storing drum.
Known yarn end holding devices either include a ring in the form of a comb or a brush located adjacent a weft releasing side end of a yarn storing end or otherwise use a whirling air flow for holding a weft yarn. However, a yarn end holding device of the former type has a drawback that a weft yarn is released while slidingly contacted with the brush or comb so that it is acted upon by a high and uneven releasing resistance and hence is not subject to a uniform tensile force. On the other hand, a yarn end holding device of the latter type has a drawback that it consumes a large quantity of air and hence a large power and accordingly a measuring irregularity is high. In addition, yarn end holding devices of such conventional types have another drawback that, if a hard twist yarn is employed, a weft yarn cannot be held assuredly and hence types of weft yarns to be used are limited.
A yarn end holding device of a different type is also known wherein a gripping disk is located adjacent a weft releasing side of a yarn storing drum and is moved back and forth so that a weft yarn may be gripped by and between a side end portion of the yarn storing drum and the gripping disk. This type of yarn end holding device, however, has a drawback that it has a complicated structure because a mounting structure for such a gripping disk becomes complicated and a weft yarn to be released is required to pass the center of the gripping, resulting in difficulty in adjustment of a gripping force so that weaving defects may occur since a weft yarn may be acted upon by a large gripping force.